Multi-Objective Optimization Design and Impact Protection Efficacy of Locally Reinforced P-TPMS Forehead Helmet...

Area of Science:

• Biomechanics
• Materials Science
• Mechanical Engineering

Background:

• Conventional helmet liners, like expanded polystyrene (EPS), face limitations in mitigating high-energy impacts, leading to potential head injuries.
• Bottom-out failure and insufficient energy absorption are critical issues in current helmet liner technology.
• Reducing the risk of skull fractures and mild traumatic brain injury (mTBI) requires advanced energy-dissipating materials.

Purpose of the Study:

• To develop and optimize a novel energy-absorbing liner for helmets to mitigate bottom-out failure and improve impact protection.
• To enhance the energy absorption capabilities of helmet liners during high-energy impacts, thereby reducing head injury risks.
• To investigate the efficacy of a locally reinforced Primitive-type triply periodic minimal surface (P-TPMS) liner in a helmet forehead region.

Main Methods:

• A finite element model of a helmet-head coupling was developed and validated against the ECE 22.06 standard drop-test methodology.
• The Box-Behnken Design (BBD) response surface methodology was employed to optimize critical design parameters: outer protective layer thickness, TPMS unit cell size, and wall thickness.
• Multi-objective optimization was used to determine ideal parameter combinations, assessing protective efficacy through head dynamic and biomechanical responses.

Main Results:

• Optimized P-TPMS liner parameters: 14.95 mm outer layer thickness, 12.23 mm unit cell size, and 3.93 mm wall thickness.
• The optimized P-TPMS liner reduced head injury criteria (HIC) by approximately 16% and peak linear acceleration (PLA) by 14% compared to EPS liners.
• Intracranial pressure and brain tissue strain were reduced below clinical injury thresholds, significantly lowering risks of skull fracture and mTBI.

Conclusions:

• The P-TPMS liner design offers superior energy dissipation through layer-by-layer buckling deformation, enhancing helmet protective efficacy.
• This advanced liner design extends impact duration and markedly improves overall helmet performance.
• Findings provide a foundation for localized heterogeneous liner designs in high-performance helmets, particularly for frontal impact conditions.